A Geophysical Investigation Searching for Archaeological Features at Sunwatch Indian Village

A near-surface geophysical survey was conducted at SunWatch Indian Village in Dayton, Ohio. The main motivations for this investigation were to evaluate geophysical methods to locate, map, and identify features associated with the SunWatch Indian Village archaeological site and to expand the area surveyed. Previous studies (Houston, 2002; Miller, 2004) have determined that burials covered with limestone slabs are relatively easy to detect and map geophysically with GPR and electrical resistivity. This was reconfirmed in this study by collecting 3D GPR data over a \u27control\u27 location previously surveyed by Houston (2002) and Miller (2004). However, similar anomalies were not observed in the other areas surveyed in this study suggesting that they are absent there. The GPR data were collected at 6 inch line spacing for 3D surveys. A comparison of 3D GPR analysis of 6 inch line spacing and 12 inch line spacing (by removing alternate lines) indicates that a 6 inch line spacing was better at defining the subtleties of limestone slabs but that the 12 inch line spacing was adequate for mapping the slab-covered burial site. Electromagnetic (EM) surveys were also conducted across the control as well as new areas but the EM did not show an anomaly at the known limestone slab-covered burial in the control area. This suggests that EM is not able to detect small, thin, resistive bodies (limestone slabs) in these conductive soils. On the other hand electrical resistivity is useful in detecting limestone slabs (Houston, 2002; Miller, 2004) but may be unable to detect more subtle conductivity contrasts likely associated with storage/ trash pits. The magnetic gradiometer surveys were successful in identifying local magnetic anomalies that correlated with an EM inphase anomaly. An interesting find was that the EM unit was able to detect in several unexcavated areas anomalies of high conductivity and low magnetic susceptibly that are believed to be associated with clusters of storage/trash pits. Another interesting find was that the EM instrument was able to detect the presence of an area of high magnetic susceptibility and low conductivity possibly indicating the location of a fire hearth or pottery kiln. Based on the results of this survey there are no new limestone slab covered burials located at SunWatch Indian Village in the areas surveyed but there is a possibility of clusters of storage/trash pits based on the EM signature. Before this study was conducted there was no definitive geophysical method of locating storage/trash pit at SunWatch Indian Village, however, this study suggests there may be a way to locate clusters of storage/trash pits using electromagnetics